Method of and means for spinning artificial silk



Oct. 2, 1934. c. c. JESSEN 3 METHOD OF AND MEANS FOR SPINNING ARTIFICIAL SILK Filed May 4, 1929 6mm 55 6. JESSEN,

.35 godet wheel.

Patented Oct. 2, 1 934 UNITE srr isisisn DIETHOD OF AND MEANS FOR SPINNING ARTIFICIAL SILK 1 Charles C; Jessen, Passaic, N. J assignor, by U mesne assignmentato Atlas Powder Company, Wilmington, DeL, a corporation of Delaware Application May 4, 1929, Serial No. 366,514

@iaims.

This invention relates to a method of and means for spinning artificial silk, and more particularly to the use of pot spinning in the manufacture of artificial silk by the cuprammonium 5 process.

Broadly stated, the invention resides in applying a retarding force to the thread at some point between the spinneret and the spinning pot or centrifuge. This retarding force puts the thread under tension and prevents the slippage of the thread over the godet wheel.

In the viscose process of producing artificial silk, objectionable slipping of the thread over the godet wheel does not occur, because the tension applied to the thread by the pot is small and the coefficient of friction between the thread and the godet wheel is large. Precipitated viscose thread contains from twenty to twenty-two percent of cellulose. Precipitated copper ammonia 20' thread contains only five to eight percent of cellulose. For a given denier of thread, it weighs more and the pull due to the centrifugal force of the thread in the pot is greater than in the case of the thread produced by the viscose process. The

.251 frictional drag of the thread produced by the copper ammonia process, as it goes through the precipitation bath, is not sufficient to prevent slippage over the godet wheel, as in the case in the viscose process.

As the thread gradually collects in the pot, the centrifugal force decreases, due to the decrease in the effective radius of the space in which the thread is being collected. This causes a decrease in the pull applied to the thread as it leaves the In the absence of the present invention, and if the thread can slip over the godet wheel, the slippage will vary with the tension applied by the pot. This will result in a skein having one end of a lower denier than the other end.

.40; Whengodet slippage is eliminated, the skein is of uniform denier throughout.

Another important feature in connection with the. application of a retarding force to the thread is that if the force be large enough, the finished 45. rayon has a subdued luster and increased opacity, and these are highly desirable qualities. The reduced luster gives the rayon an appearance much like that of natural silk, and the increased opacity gives greater covering power.

In the accompanying drawing, which constitutes a part of the present application, the figure shown is a diagrammatic view illustrating the invention.

In the drawing, 5 designates a spinneret dislposed in such position as to discharge the copper (or. 1H;

ammonia solution into a precipitating bath 6, in tank 7. The various strands 8, from the spinneret, are led over a tension device 9, hereinafter described, thence over a godet wheel 10, and downwardly from the latter through a guide tube 12,

into a spinning pct 13, where the various strands from the spinneret which, up to this point, have been in parallelism with each other, are twisted by the action of the spinning pot to constitute a single thread, the cake of spun thread being indicated at 14, upon the inside of the pot. All of the mechanism described is that commonly used, except the tension element 9. This may be of any desired form. For purposes of illustration, I have shown this element 9 as consisting of a pulley, over which the thread passes. I have found a pulley of five inch diameter and two and one-half inch face to be desirable for the purpose. This pulley is, preferably, mounted upon bearings that are as nearly frictionless as possible, and its lower portion is submerged in the precipitating bath. However, it is clear that any suitably shaped guiding surface over which the thread may pass will serve the purpose sought; namely, that of applying a retarding force to the thread between the time that it leaves the spinneret and the time that it enters the centrifuge, though, preferably, this tensioning device is applied between the spinneret and the godet wheel.

In the form chosen for purposes of illustration, namely, the rotating wheel 9, the amount of tension applied to the thread depends on the position of the wheel, its size, degree of submergence, viscosity of the bath, etc., and the tension imparted by any guiding surface employed will depend on a number of factors, such as the size, shape and position of such surface and the viscosity of the sodium hydroxide precipitating bath.

While I prefer to mount the tension wheel 9 upon a perfectly free bearing and to wholly or partially submerge said wheel in the precipitating bath, it is to be understood that it is within the scope of the invention to impart any degree of friction to the bearing of the wheel 9. This is common practice in tensioning wheels for threads in many of the arts. While I have stated that the invention relates particularly to the manufacture of artificial silk by the cuprammoniurn process in which godet slippage is more likely to occur than in the viscose process, I do not wish it to be understood that I disclaim the use of the invention in connection with viscose processes. Upon the contrary, it is clear that to the extent that any slippage may occur in viscose processes, my method is capable of preventing the same'and to the extent that my method is applicable in the manufacture of artificial silk by any process, I desire to claim the same. j

It is to be understood that the invention includes within its purview whatever changes 'fairly come within either the terms or the spirit of the appended claims.

Having described my invention, what I claim 1s: n 1. The hereindescribed method of preventing slippage of artificial silk thread with respect to the godet wheels of artificial silk spinning machines, wherein' the thre'ad passes'from a precipitating bath over the godet wheelto a cen trifugal spinning element, which consists of tensioning the thread upon the precipitating bath side of the godet wheel to the extent necessary to compensate for the variation in pull of the centrifugal spinning element and to prevent slippage of the thread with respect to the godet wheel but not to an extent to cause permanent deformation of the thread. V

2. In a machine for spinning artificial silk, the combination with a precipitating bath, of a spinneret discharging thereinto a centrifugal spin pot, a godet wheel over which the thread passes before entering'the spin pot, and a pulley at least partly submerged in the said precipitating bath over which the thread passes on its way to the godet wheel, the size of said pulley and the degree of friction thereon being such that, sufficient tension is imparted to the thread to prevent slippage of the same with respect to the godet wheel but not enough tension is imparted to the thread to permanently deform the same.

' CHARLES C. JESSEN; 

